High surface area hydrate

Several years ago it was discovered that a tricomponent system (1,3) consisting of hexamethylenetetramine, resorcinol, and high surface area hydrated silica (HRH system) when incorporated into a rubber compound, brought about extremely good adhesion to many types of fabrics. Subsequently, the system was also evaluated in elastomer composites for... 

Production of High Surface Area Hydrated Limes 219... 

Improved absorbents have been developed — see section 20.6, which describes the production of hydrated limes with high specific surface areas. [29.6] mentions a calcium lignosulfonate-modified hydrated lime for the high temperature injection process (presumably a high surface area hydrate). 

Section 20.6 describes two processes for the production of high surface area hydrated lime, with BET areas of 30 to 50m /g, and median particle sizes of about 2 Lun. One uses a methanol-water mixture for the hydration process, while the other uses water containing an additive. The higher surface areas enable the required acid gas emission concentrations to be achieved at lower levels of excess hydrate and with reduced amounts of waste material. 

Some catalyst supports rely on a relatively low surface area stmctural member coated with a layer of a higher surface area support material. The automotive catalytic converter monolith support is an example of this technology. In this appHcation, a central core of multichanneled, low surface area, extmded ceramic about 10 cm in diameter is coated with high surface area partially hydrated alumina onto which are deposited small amounts of precious metals as the active catalytic species. 

Activated aluminas. Activated alumina is a porous form of aluminum oxide (A1203) with high surface area, manufactured by heating hydrated aluminum oxide to around 400°C in air. Activated aluminas are mainly used to dry gases and liquids, but can be used to adsorb gases and liquids other than water. 

Hydrated hydraulic limes, 15 55 Hydrated lime(s), 15 28, 61 aquaculture application, 3 207 high surface area, 15 55 production of milk of lime from, 15 56 quality control for, 15 70 reactions, 15 45... 

The measured uptake of CPA and PTA over the three activated carbons [55] is shown in Figure 6.28, and the trends predicted by the RPA model in Figure 6.27 are at least qualitatively observed. However, at high pH, over the two highest-surface-area carbons (CA and KB), uptake is about half of that predicted by the RPA model. The discrepancy was explained [55] by steric exclusion of the large Pt ammine complexes, believed to retain two hydration sheaths [15,19], from the smallest micropores of the high-surface-area activated carbon. 

Proximity to the phase boundary, and the need to supply energy to dissociate the hydrates, will control the rate of dissociation and thus the economics. Because conductive heat transfer controls hydrate dissociation, hydrates closer (in temperature and pressure) to the phase boundary will be most economical to dissociate. Heat transfer limitations indicate that high surface areas (thin layers) are most economical. 

The analysis of smoke and soot formation from polymers during combustion has been extensively studied 50,51 however, less is understood on how hydrated fillers influence this mechanism. It is likely that smoke reduction results from the deposition of carbon onto the high surface area oxide surface, produced on the decomposition of the filler.38 The volatilization of carbonaceous residue as carbon oxides then occurs, reducing obscuration effects from the smoke. 

The deposition of increasing amounts of titania onto silica preserved the high surface area and amorphous character of the material even at monolayer coverage. The coordination of titanium in hydrated environment changed from tetracoordinated up to hexacoordinated upon increasing the loading. 

Other solids are used as extenders of cement slurries because, with a high surface area and a strong interaction with water, they immobilize a significant fraction of the water. This hydration water is structured and thus contributes to the rheological behavior of the suspension as part of the solid phase. Materials of this type are diatomaceous... 

Lipases are manufactured by fermentation of selected microorganisms followed by a purification process. The enzymatic interesterification catalysts are prepared by the addition of a solvent such as acetone, ethanol, or methanol to a slurry of an inorganic particulate material in buffered lipase solution. The precipitated enzyme coats the inorganic material, and the lipase-coated particles are recovered by filtration and dried. Various support materials have been used to immobilize lipases. Generally, porous particulate materials with high surface areas are preferred. Typical examples of the support materials are ion-exchange resins, silicas, macroporous polymers, clays, etcetera. Effective support functionality requirements include (i) the lipase must adsorb irreversibly with a suitable structure for functionality, (ii) pore sizes must not restrict reaction rates, (iii) the lipase must not contaminate the finished product, (iv) the lipase must be thermally stable, and (v) the lipase must be economical. The dried particles are almost inactive as interesterification catalyst until hydrated with up to 10% water prior to use. 

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